Metering and timing apparatus for telephone systems



Jan. 12, 1932. P. H. HELLNER METERING AND TIMING APPARATUS FOR TELEPHONE SYSTEMS 4 Sheets-Sheet Filed June 19, 1930 \N) WNW,

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IIIII ID I- NQFFRQ /NVEN TOR PH HELLNER a e/w ATTORNEY Jan. 12, 1932. L E 1,840,359

METERING AND TIMING APPARATUS FOR' TELEPHONE SYSTEMS Filed June 19, 1950 4 Sheets-Sheet 2 A 4271; EORD F/c-r. 3

/N l EN 70/? PH HELLNER ahavm'w ATTORNEY Jan. 12 1932. P. H. HELLNER METERING AND TIMING APPARATUS FOR TELEPHONE SYSTEMS Filed June 19, 1930 4 Sheets-Sheet 3 n h. M w 6 Wu WNR. 0v

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METERING AND TIMING APPARATUS FOR TELEPHONE SYSTEMS Filed June 19, 1950 4 Sheets-Sheet 4 Fast B 70L L CORD lNVENTDR Ph. HELLNER BY Patented Jan. 12 1932 UNITED STATES PATENT OFFICE PONTUS H. HELLNER, or ANTWEREBELGIUM, assrenon *ro WESTERN ELECTRIC com- PANY,'INGQRPORATED, or NEW YORK, N. Y., A CORPORATION or NEW YORK METERING AND TIMING APPARATUS FOR- TELEPHONE SYSTEMS Application filed June 19, 1930, Serial No. 462,213, and in the Netherlands Jul 5, 1929.

. This'invention relates to automatic timing and rating of interofiice telephone calls and is more particularly concerned with the automatic recording, metering, andsupervision The callingsubscribers meter is then operated in accordance with the sum total of all these impulses. The circuits also provide a signal toin the first connectin cord in the train for denoting the termination of the periodof conversation time for which the charge was made. It includes, as well, other circuit conditions for providing visual super vision of the call by the operator at the orig inating office during conversation and also supervision at the intermediate and terminating operators positions during the set up of the call and at disconnection.

Long distance telephone systems may be divided broadly into two classes having, respectively, delay and no-delay methods of operating. In accordance with the delay method, the calling subscriber, after giving his number and that of the wanted subscriber to the recording operator restors the receiver. The operator writes both numbers upon a ticket and transmits it to a toll operator who has access to the toll lines leading in the wanted direction. The toll operator thenproceeds to call the wanted subscriber through the medium of the various inter- 'mediate offices through which the connection must be routed in order to reach the called station and when the called subscriber answers, recalls the callingsubscriber. In accordance with this method of establishing connections fewer toll trunks are required since the calling subscribercan be made to wait until a toll line is available;

In the no-del ay method of operating, com-:

monly known as the CLR method (combined line and recording), the operator who formerly onlyrecorded the calling and wanted numbers upon a ticket also has access to toll lines leading in the wanted direction. By

this methodthe calling subscribers Waiting time is reduced to such an extent that it is no longer necessary for him to restore the receiver and be called back after the connection is established. This makes it possible for the operator to expedite connections and per- A no-delay service can also be furnished 011 long distance lines during the busy hour if the greater long line costs can be compensated for by lower operating costs. One of the chief causes for the reduction of operating costs of CLR service is the elimination of the expensive ticket distributing system when the complete toll line multiple is accessible to the recording operator. It is the object'of the present invention to eliminate the necessity of ticketing and to perform automatically such functions as now require ticketing.

In the establishment of long distance telephone connections, successive attempts have been made to automatically check the conversation time and provide visual supervision of the call by the originating toll operator, but it has been necessary for the operator, in such cases, to record the call and perform metering operations as well. It is a further object of the present invention, therefore, to perform the function of metering automatically as well as to provide for supervision of the call so that the task of the operator in recording metering information is obviated. lVhen the call is established there will be no further function to perform beyond taking down the connection when signaled to do so.

In accordance with the present invention,

therefore, one specific embodiment of which is disclosed herein by way of illustration, this is accomplished in the following improved manner: An individual timing impulse circuit capable of generating and transmitting a definite number of pulses in either direction is provided in each interofiice trunk; a given number of such pulses for any trunk representing the charge for the use of the trunk in any connection for which it is taken into use for a given'unit of conversation time. These pulses are transmitted to and recorded in suitable switches in the recording trunk immediately after the called sub scriber answers. These pulses remain so registered during the f conversation period. When the conversation is terminated another switch in the recording trunk is connected to the subscribers meter and also to the switch on which'the impulses are registered. The subscribers meter is then operatedonce for each pulse so registered, and, with each pulse, the metering switch is stepped until the number of steps taken equals the number of steps recorded on the register switch. In this manner the subscribers meter is operated as many times as is necessary to satisfy the register switchwwhich was stepped by the pulses received from the trunks in the tolltrain'. If the called subscriberdoes not answer, the calling subscribers meter, of course, is not operated even though the. pulses representing the charge to be made for the callhave been received and recorded in the registering switch of the recording trunk.

In addition to the usual flashing recall and switchhook supervision, the originating operator is also advised by a special interrupted lamp signal in the cord circuit as to when the standard period of conversation is terminated. The supervision of the call, other than this special signal, is furnished either on an alternating or direct current basisin the well-known manner depending on the nature of the connection.

A clearer conception of the scope and purpose of the invention will be obtained from a consideration of the following description taken in connection with the attached drawings in which I Fig. 1 shows schematically an interoffice toll connection through an intermediate of-' Fig. 2 shows the recording trunk and associated call charging control circuit; 4 Fig. 3 shows a simplified toll cord at the left and the outgoing interoflice trunk at the right;

Fig. 4 shows the incoming end of the interoffice trunk whose outgoing end is shown in Fig. 3';

Fig. 5 shows another simplified toll cord, a schematic representation of an interoflice trunk similar inevery respect to the interofiice trunk shown in Figs. 3 and 4, a simplified completing cord and a subscribers line.

It will be assumed in the connection described hereinafter that the recording trunk is reached by the calling subscriber in any standard and well-known manner; For the purpose of this description, Fig. 2 illustrates schematically the conditions prevailing in the case of an automatic subscriber connected to a recording trunk 'by way of two group selectors;

Establishment of connection Referring now to Fig. 1 a brief description of the general manner of operation for a toll call routed through three ofiices, namely, A, B and O and in which the operators A, B and O mentioned hereinafter refer to the operators respectively at each of these offices, will be given. When the A operator is informedthat a recording trunk RT is calling she inserts theanswering plug of the A toll cord into the jack of the recording trunk and ascertains from the calling subscriber the ofiice,.name andnumber of the wanted subscriber. She then takes into use an outgoing trunk OTB by inserting the calling plug of the A toll cord into the jack thereof and thereby extends the connection to. the incoming trunk ITB terminating in intermediate ofiice B through which the terminating office O is to be reached. The B operator takes up the call with the answering plug of the B toll cord and, by a proceduresimilar to the one which has been described as taking place at the A oflioe, extends the connection to the O ofiice by way of outgoing trunk OTO and incoming trunk ITO. The operator at theO office then takes up the call with the answering plug of the O completing cord and completes thereby the connection to the, called subscribers line with the. calling plug of the O completing cord. YVhen thecalled subscriber, answers, an answering signal is repeated back along the toll train 'to the timing circuit in the recording trunk RT which, in turn, sends back a signal to the first outgoing trunk OTB to release the group of pulses designating the charge for the use of the trunk. OTBITB. These pulses are then transmitted to and registered in the recording trunk registering switch and remain so registered until the'end of the conversation. When the first trunk has finished sending its impulses it,in turn, transmits a signal to the incoming end of the trunk ITB which signal is then repeated to the next outgoing trunk OTO. This trunk now transmits its own impulses back to the timing circuit of the recording trunk and. the process is re peated with each trunk in the train until all the groups of pulses'individual to each trunk in the train have been transmitted to the recording trunk and recorded-in the registeringswitch therein. When the conversation is completed, means in the recording trunk cause the calling subscribers meter to be operated a number of times in accordance with all the pulses recorded.

Refer now to Figs. 2, 3, 4, and 5 placed in juxtaposition to each other in the order named, for a detailed description of the circuit operations involved.

When the calling subscriber establishes a connection to the recordingtrunk, relays 241 and 215 operate over a circuit from battery on winding of relay 241, repeating coil winding 206, subscribers loop extending through the 'line finder and the two group selector circuits, repeating coil winding 207, winding of relay 215 to ground. Relay 241 operates relay 22 1 while circuits controlled by the contacts of relay 215 are operated to signal the A operator in any well-known manner. When the A operator is informed that a recording trunk is calling she inserts the answering plug l? of the A toll cord into the recording trunk jack K. Key 305 of the cord is operated, the operators telephone circuit is connected across the line in the well-known manner, and winding of relay 229 of the recording trunk are connected in series with the'relay 307 of the cord in the following circuit; ground through both windings in series of relays 229, top back contacts of relay 223, jack sleeve 232 of recording trunk jack K, sleeve conductor 302 of the cord, operated outer left contacts of 'key 305, Wind ing of relay 307 to battery. Relay 307 is marginal, does not operate in series with both windings of relay 229 and therefore no circui' is closed for lamp 303 which remains extinguished. No useful function is performed by the relays this time. The operator ascertains from the calling subscriber the ofliee and number of the wanted subscriber and inserts thereafter the calling plug Q of the A cord into the iack T of the outgoing trunk OTB leading in the wanted direction, which, it assumed, is through intermediate office B. A circuit is now closed foroperating re- 323 from battery through the winding of relay 306, operated right outer contacts of key 305, cord sleeve conductor 310., jack sleeve conductor 311, top contacts of relay 322, lower winding of relay 323to ground. The circuit from battery through the winding of relay 306 has a parallel path by way of the top back contacts of relay 320 and normally closed inner top contacts of relay 323, winding of relay 327 to ground on the bottom outer most make contacts of relay Relay 327 also operates at this time. Relay 323, on operating. closes a locking circuit over its upper win ding and its top inner front contacts to ground through the winding of relay 327 over the previously described path so that relays 323 and 327 are now locked in series. Relay 323 when operated, connects ground through interrupter dle right contacts of key 305, lamp 307, re-

sistance 340, battery.

When additional trunks are taken into use at other switchboards in extending the connection there-through and the cords at the respective switcliboards are inserted into the outgoing trunk jacks of these trunks, similar circuit conditions are closed and the flashing lamp signal is similarly given at these switchboards.

Relay 329 now operates from ground at the top cuter front contacts of relay 323 and connects battery through resistance 3 14, lower back contacts of relay 320, top front contacts of relay 329, winding of the outgoing trunk repeating coil, conductor 3&2, whiting 401 of the incoming trunk repeating coii, top back contacts of relay e05, winding of relay 407 to ground, 0 aerating this relay. R-elay 107 closes ground its front contacts and operates relay 413 over its upper windin and also relay 411 over its upper winding. Relay 1-13 operates the switchboard busy signal 413 over a circuit from battery on the bottom inner front contacts of relay 13, winding of signal 118, resistance 428 to ground. This indicates to the operator at the B OfllCi) that a call is awaiting on the trunk. ll hen the B operator plugs into jack F with the answering plug D of the B toll cord and takes into use another outgoing trunk, such as OTO-I1O, iy inserting calling plug into jack H of the outgoing trunk leading to oflice C, schematically indicated in Fig. 5 and similar in circuit structure and appara us arrangement to the trunk shown in 3 and 4, the above operations are repeated at the outgoing OTC and the incoming end ITO of this second trunk and the C operator after inserting answering plug it of the completing cord into jack E and inquiring the wanted line in the well-known manner of the preceding operator, completes the connection by inserting the calling plug S of the completing cord into jack J of the called subscribers line and rings the said line in the well-known manner. Only such portions of the completing cord O are shown as is necessary to a complete understanding of the present embodiment of the invention. All other elements of the said cord are well-known in the telephone art and are therefore om1tted. The following operations take place in the trunk circuit OTCITG as a result of the called subscriber removing his receiver from the hook, except those operations which are specific to other circuits such as, for example, the C completing cord. Since, circuit OTC- ITC is only diagrammatically represented in Fig. 5, the description will be referred back conductor 531, repeating coil winding 533,

windingof relay 528, battery. Relay 528 connects battery throughhi 'h res1stance 529 to the repeating coil winding 535, thence to ing conductor 516, ring conductor 520 in trunk ETC corresponding to conductor 420 of the incoming trunk, retard coil 427, lower bacl: contacts of relay 405,'both windings in series of relay 410 to ground, thereby operating relay 410 in incoming trunk ITC. A

path is now closed to operate relay 409 from ground on the top inner front contacts of relay 410, and when relay 409 operates, it locks over its inner front contacts to ground at the bottom front contacts of relay 413. The operation of relay 410 closes a circuit for relay 426 from ground at the contacts of relay 407 bottom outer front contacts of relay 410 to the winding of relay 426 and also to the upper winding of relay 411 causing relay 426 to operate; relay 411 already having been operated from the contacts of relay 407. When relay 426 operates however, the closure of its outer fr nt contacts connects the lower diiferentia-l winding of relay 411 to ground on the contacts of relay 407 over the path previ usly described, thereby releasing relay 411. Battery th ough resistance 431 is now connected to the winding of relay 321 in the outgoing end of the trunk OTC, by way of the top outer front contacts of relay 410, winding 403 of the incoming trunk repeating coil, conduct-or 343, outgoing trunk repeating coil windirg 337. top outer back contacts of relay 335, winding of relay 321, to ground. operating this relay. Relay 321 operates relay 320 over its lower winding and relay 320 disconnects battery through resistance 344 at its bottom back contacts from conductor 342 thereby causing the release of relay 407 in the incoming trunk ITG. Relay 1407 releases relay 426. The operation of relay 320 closes a circuit for relay 331 from ground on the bottom inner front contacts of relay 320 to upper winding of relay 331 operating this relay and locking it through the same winding over its bottom outer contacts to ground on the bottom middle front contacts of relay 323. Relay 331 disconnects interrupter 336 at its inner back contacts, releasing relay 306 and, in consequence, extinguishing 'the cord supervisory lamp 307 or specifically lamp 507 of the B toll cord.

V] hen relay 321 operates, battery is connected on its front contact to the lower winding of relay 320 as described, but also to winding of relay 326, and winding of relay 410 inthe next preceding trunk in the train which, in this case, would be trunk OTB 1TB by way of the bottom front contacts of relay 329, retard coil 341, ring conductor 313 of the trunk, cord conductor 309, ring conductor 420 of the next preceding trunk, retard coil 427 of the next preceding trunk, bottom back contacts of relay 405 of the next preceding trunk to both windings in series of relay 410. The effect of this signal is the operation of relay 410 in the incoming end of the next preceding trunk and the consequent operation of relay 321 in the out-going end of the same trunk. In this way the resistance battery signal is repeated in every trunk of the train. W e will assume, therefore, that the operations which have taken place in trunk OTCITC have been repeated in the trunk OTBITB immediately preceding and', remembering that there is no other intermediate trunk between OTB- ITB and the recording trunk, we will proceed to describe the effect of the transmission of the resistance battery signal from trunk OTBITB to the recording trunk.

V] hen relay 321 of trunk OTBITB opcrates, battery is connected over its front contacts to the lower winding of relay 320 and also to relay 326 as described. The other end of the winding of relay 326 is, at the same time, connected in series with the upper winding of relay 226 in the recording trunk circuit by way of the bottom front contactsof relay 329, retardation coil 341, conduct-or 313, cord conductor 309, conduct-or 231 of the recording trunk, winding 212 of the recording trunk repeating coil, bottom back contacts of relay 223, upper winding of relay 226 to ground. Relay 226 operates over this circuit and looks over its lower winding in circuit to ground on the top outer back contacts of relay 223 by way of the top contacts of relay 224 and its own bottom inner locking contacts. Relay 326, however, does not operate. Relay 320in the outgoing trunk circuit also connects relay 327 to the sleeve of the trunk over the top front contacts of relay 320 so that the flashing recall circuits may be controlled by relay 327 in any suitable manner. Relay 224 is operated at this time, it being held locally from the contacts of the recording trunk supervisory relay 241 as previously described. When relay 226 operates, a circuit is closed to the,

timing switch magnet 227 by ground on the top front contact of relay 226. The timing switch magnet starts the associated brush 242 to advance over terminals 16. When the timing switch wiper 242 reaches contact 1 of the arc, relay 220 operates over the switch brush 242 over a circuit from ground on the bottom middle front contacts of relay 226, normally made top middle back contacts of relay 223, wiper 242, contact 1, winding of relay 220 to battery. The operation of relay 220 connects the low resistance relay 219 to the bottom front contacts of relay 220 in parallel with the upper winding of relay 226- and this combined parallel circuit of relays 226 and 219 is connected to relay 326 in the outgoing trunk by way of the bottom con tacts of relay 223, repeating coil winding 212, conductor 231, cord ring conductor 309, trunk ring conductor 313, retard coil 341, bottom 7 front contacts of relay 329, winding of relay 326 to battery on contacts of relay 321. Relay 219, in parallel with relay 226, reduces the effective resistance in series with relay 326 so that relay 326 now operates. Relay 217 also operates from'ground on the top front contacts of relay 220 through the front contacts of relay 219.

When relay 326 in the outgoing trunk operates, it connects slow speed interrupter 325 to relay 316 by way of the top outer front contacts of relay 326, top back contacts of relay 319, upper winding of relay 316 to battery on the top normally made contacts of relay 315, causing relay 316 to be operated during the grounded period of interrupter 325. Relay 316 energizes and closes its bottom inner grounded front contacts to both its own lowerwinding and also to lower winding of relay 315; Relay 316 also closes its top front contacts and connects grounded impulse interrupter 317, through resistance 318to' the grounded side of the winding of relay 326. During the interval when the grounded segment of interrupter 317 is connected to the winding relay 326, this ground is also connected to the windings of relays 2-19 and 226 in the recording trunk and shortcircuits these relays. The circuit path is as follows: ground on interrupter 317, low resistance 318, top contacts of relay 316, bottom front ccntacs of relay 329, retard coil 341, trunk ring conductor 313, cord ring con- Relay 226 is held locked through its lower winding as previously described but relay.

219 releases with each pulse of ground coming from interrupter 317 to perform a function to be described hereinafter. Relay 217 which holds operated over the front contact of relay 219 is a slow release relay and does not release during the pulse release of relay 219. Likewise, relay 220 is a slow release relay so as to hold operated over the terminals 15 of the timing arc of switch 227 over which brush 242 is advancing.

lVhen interrupter 325 makes with an insulated segment and removes ground from the top outer front contacts of relay 326, relay 315, previously short-circuited over its lower winding by ground on the locking contacts of relay 316 and ground through the interrupter 325, now operates from ground on the aforementioned locking contacts of relay 316, lower winding of relay 315, upper winding of relay 316, to battery on the normally made top cont-acts of relay 315 and locks up on its upper winding from battery on its top front contacts, both windings in series to ground on the locking contacts of relay 316 and, in so doing, disconnects the battery from the upper winding of relay 316, causing this relay to hold only on its lower winding from ground on its locking contacts in series with battery through the upper winding of relay 315. When the interrupter 325 again connects ground to relay 316, it shortcircuits its lower winding, causing it to release, but relay 315 will now hold over a local circuit from battery on its upper front contacts, upper winding to ground on the interrupter 325 and will continue to so hold until ground is removed by the operation of relay 319 as described hereinafter. During this cycle of counting operations of relays 316 and 315, interrupter 317 is connected to the ring conductors of the outgoing trunk, cord and recording trunk, as already described, and intermittently releases relay 219 of the timing circuitin the recording trunk as already described. During one complete revolution of interrupter 317 the timing relationship between interrupter 325, relays 315 and 316 is such that relay 316 is held operated for a length of time just sufiicient for interrupter 317 to make one complete revolution. At each release of relay 219, a circuit for the register switch magnet 216 is closed from ground on the top front contacts of relay 220, back contacts of relay 219, front contacts of relay 217, winding of switch magnet 216, to battery. A parallel circuit is also closed to relay 214 which closes a supplementary ground to the switch magnet 216 so that the stepping of the switch is insured if relay 219 should reoperate before the switch magnet has operated sufficiently to break its interrupter contacts. The circuit controlled through the back contacts of relay 219 causes the switch to take as many steps asthe intermittent release ofrelay 219 closes the back contacts of this relay. The length of time, therefore, which the grounded and insulated segments of interrupter 325 allow for each cycle of operations of relays 315 and 316, and the number of grounded segments on the circumference of interrupter 317 determines the number of impulses sent by the interrupter 317, the number of times relay 219 is operated I and released for the particular outgoing trunk which is transmitting the pulses and the"consequent number of steps taken by switch 216. For outgoing trunks for which various charges areto be made, different interrupters 317 may be used while interrupter 325 can be common to all of the trunlrs. If it is desired to vary the charge at any time,

this can be done by substituting for interrupter 317 any other interrupter having the required number of impulses for the new charge.

When relay 316 releases, relay 319' is operated by a circuit over the bottom back contacts of relay 316, bottom contacts of relay 315 to ground on inner front contacts of resending its impulses, relay 319 connects battery through resistance 344 over its bottom front contacts and top front contacts of relay 329 to the winding of relay 407 in the incoming trunk by way of winding 332 of the outgoing trunk repeating coil, conductor 342, winding 401 of the incoming trunk repeating coil, top back contacts of relay 405 to the winding of relay 407. Relay 426 again energizes over the circuit previously described and the ground on the inner front contacts of relay 426, back contacts of relay 411 to both windings of relay 410, short-circuits the bottom high resistance winding of relay 410. The relay'corresponding to relay 326 in the succeeding outgoing trunk circuit OTC is connected to the ring conductor of the trunk and connecting cord to the pres cedlngincoming trunk as relay 326 of the outgoing trunk OTB is connected to the ring conductor of trunk OTB, connecting cord and recording trunk, so thatthe upper winding of relay 410 of the incoming trunk ITB is in series with relay 326 of the outgoing trunk OTC over the fGllOWll'lg circuit: ground through the upper low resistance winding of relay 410, bottom back contacts of relay40 5, retard coil 427, trunk ring conductor 420, cord ring conductor 509, ringconductor 513 of the outgoing trunk OTC, re

tard coil 3410f outgoing trunk OTC, bottom front contacts of relay 329 of the outgoing trunk OTC to winding of relay 326 of the outgoing trunk OTC. -Relay 326 in the outgoing trunk OTC now operates to initiate impulses in the same manner as described for the outgoing trunk OTB and these pulses are now transmitted back to the recording trunk as follows:

Each time a ground is presented to conductor 313 of the succeeding outgoing trunk, such as OTC, by the interrupter 317 located therein, the upper winding of relay 410 in the preceding trunk is short-circuited, causing this relay to release and disconnect resistance battery 431 from conductor 343 connecting with the outgoing end of the trunk. This releases relay 321 which, in turn releases, relay 320. Since relay 219 in the recording trunk is held by battery through the front contacts of relay 321 in series with the winding of relay 326, the release of relay 321 will cause a corresponding release of relay 219. Relay 326 also releases, thereby releasing relay 319 by the removal of locking ground from the front contacts of relay 326. lVith each succeeding ground pulse the foregoing operation is repeated, causing relay 219 to be impulsed a corresponding number of times and register switch 216 in the recording trunk to be stepped again a number of timescorresponding to the impulsestransmitted from the succeeding trunk in the train. When the short-circuit from the last impulse is removed, relay 410 reoperates, reconnects battery through resistance 431 to the outgoing end of the trunk circuit, operating relay 321 which, in turn, reconnects battery through the windingof relay 326 in the first outgoing trunk to relay 219 in the recording trunk.

If another trunk were connected to the train beyond trunk OTCITC the operation of relay 319, in the. trunk immediately preceding, at the completion of the pulsing cycle, would cause the operation of relay 407 in the incoming end of the same'trunk, in the same manner as described for trunk OTB ITB, the short-circuit of the high resistance winding of the associated relay 410 and the transmission thereafter of the signal to send pulses from the succeeding trunk by the operation of relay 326 therein. The transmission of pulses so started will then be the' same as already described, namely, the intermittent short-circuiting of relay 410, its consequent release and the subsequent intermittent removal of battery on the ring conductor to the immediately preceding trunk;

the signal being repeated until'the first outgoing trunk is reached, in which the removal of battery from the ring conductor by the re lease of relay 321, effects the release of relay 219 in the recording trunk.

Referring now to the operations in the recording trunk which have taken place simultaneously with those described above, the op- T31:

' leaves the group of terminals designated 1-5 of the timing are. The time taken for switch 242 to arrive onterminal 6 represents the standard period of conversation, and the travel of the switch brush over the timing arc is regulated in any suitable manner by the operating con'ipany. l/Vhen switch brush 242 leaves terminal 5, relay 220 releases in turn disconnecting relay 219 from conductor 231 so that relay 326 in the outgoing trunk releases, but relay 226 does not release since it is held locked over the path previously de scribed. Timing switch magnet 227, therefore, will continue to be energized and advances the switch brush 242 to terminal 6 thereby measuring the time to that terminal as the standard conversation period.

WVhen the conversation has terminated, and it is assumed in this case that it terminates before switch brush 242 reaches terminal 6, and the calling subscriber restores his receiver, relays 241 and 215 release. Relay 241, in turn, releases relay 224. Relay 224 releases relay 226. Interrupter 225 is now connected over the bottom outer back contacts of relay- 226 and bottom contacts of relay 224 to operate relay 223 which locks over its top middle front contacts to oil-normal ground on the contacts of the are associated with brushes 234 and 235 respectively. Arcs associated with brushes 234. 236. 237'anr 238 are associated with switch magnet 216, while arcs associated with brushes 235, 213, 239 and 240 are associated with switch magnet 218. Ilhe former of these two switches has been stepped by pulses under the control of relay 219 aspreviously described, while the latter is still in its normal position. Relay 221 is now intermittently operated over an interrupted circuit from ground on interrupter 233, brush 236 and associated arc contact, top outer back contacts of relay 222, top inner frontcontacts of relay 223, winding of relay 221 to battery; Relay 221 intermittently connects battery over its top front contacts and low resistance 200 to conductor 210 of the recording trunk, cooperating group selector brush 211, winding of relay 204 in the local group selector. to ground operating this relay. Each time relay 221 operates and connects battery to conductor 210, relay 204 operates and a battery through resistance 205 is then connected by this relay over the third wire of the first group selector to energize a relay 203 in the local line finder circuit which in turn energizes relay 202 over an obvious 221 also steps switch2l8 in a circuit from ground on the bottom contacts of relay 221, bottom back contacts of relay 222 to battery through the winding of switch 218 so that this switch takes one step for each impulse sent by the relay 221. It is evident, therefore, that each time the subscribers meter 201 is operated, switch 218 takes one stop.

lVhen the brushes of switch 218 reach the same correspondin position on their respective arcs as those occupied bv the brushes of switch 216, relay 222 is operated from ground on brush 237, the arc contact upon which it is standing, corresponding arc contact engaged by brush 239 of switch 218 to winding of relay 222. Relay 222 looks to ground on brush 238 and associated commoned arc contacts. Relay 222 disconnects switch magnet 218 at its bottom back contacts and opens the circuit of relay 221 at its top outer back contacts, thereby releasing this relay. The release of relay 221 opens the metering impulse circuit to relay 204. Relay 222 also closes a self-stepping circuit for switch 216 from ground on its top inner front contacts causing it to return to normal at which time the circuit for relay 222 is opened at the normal arc contact connecting with brush 238 and thereby causing switch 216 to stop. A parallel path is also closed to relay 214 during the returning to normal of switch 216, but since relay 217 is normal at this time the operation of relay 214 performs no useful function. A self-stepping circuit is now formed for switch 218 from ground on brush 237 of switch 216 and its normal arc contact, the olf-normal commoned contacts and brush 240 of switch 218 causing switch 218 to return to normal. lVhen switch 218 reaches normal the selfstepping circuit is disconnected by brush 24.0 engaging its normal contact on the associated arc and relay 223, which is also looked to oilnormal arcs associated with brushes 234 and 235 now releases. The release of relay 223 removes ground from the top middle front contacts to conductor 209 which, when grounds from other parts of the circuit are removed, serves to keep the trunk busy as long as the registering circuit of the recording trunk is off-normal.

If the conversation extends beyond the predetermined interval of time as measured b the time taken for the timing switch brush 242 to reach terminal 6. 224. will not release and the above described operat ons will not take place. In this case relay 226 is still locked and the ground on its bottom middle front contacts is eXtei-ided by way of the top middle normally made contacts of relav 223 to the switch brush contact 6 of thetiming arc and operates relay 228 over its lower winding. Interrupter 208 now connected through upper winding of relay 228 and its locking contact, s eeve conductor 232 of the recording trunk ack. sleeve conductor 302, normally made outer left contacts of key 305, lamp'303, resistance 338 to battery. Lamp 303 in the A operators cord circuit is now flashed in a particular manner to apprise the operator that the maximum time for the connection has elapsed. Should the subscriber desire to talk for another pe riod of time the conversation proceeds without any disturbance- The timing switch wiper 242 again engages contact 1 of the timing arc, relay 220 is operated and relays 219 and 226 are again placedin parallel to the ring conductor of the connection. Relay 321, being operated and relay 319 released, the charging impulse circuit intrunk OTB functions again and an additional set of impulses is registered by switch 216 in the manner previously described. Similar pulsing operations, followed by corresponding registration of the pulses by switch 216 then takes place with respect to all the trunks in the train in the manner described. When the subscriber restores the receiver, the operation of the subscribers meter then takes place previously described except that, in this case, the meter is operated in accordance with the total number of pulses recorded in the pulse recording circuit. I

t will be noted that the present embodiment of the invention is disclosed with relation to two-way two-wire interoffice trunks so that the charging impulses must be transmitted in either direction depending upon which end of the trunk is used as the outgoing end. In the above description it has been assumed that the part of the trunk shown in Fig. 3 serves as the outgoing end of a trunk leading to cities B while that part of the same trunk shown in Fig. 4 is the incoming end at oflice B. A consideration of the above figures. however, discloses that both ends of the trunk are perfectly symmetrical both with respect to the charging impulse equipment and also as regards switchboard signals so that the incoming end of the trunk may function as the outgoing end and vice versa. Thus the call may originate in office B, for example, for a subscriber in ofiice A or beyond. The charging pulses would then have to be transmitted to a recording trunk in oflice B by the trunk shown in Fig. 4, now serving as an outgoing trunk, connecting with office A. For this purpose the impulse circuit shown by relays 423, 424, 422, 415 and interrupters 414 and 425 are used for the purpose and the operation of thiscombination is the same as has been described for the impulse circuit shown'for the trunk in Fig. 4 which is used to transmit pulses in the opposite direction.

The release of the connection will now be described: When the calling subscriber restores the receiver the recording trunk supervisory relay 241 releases and short-cincuits the right hand high resistance. winding of sleeve relay 229 thereby closing a cir-l cuit from ground on the back contacts of relay 241, left hand winding of relay 229, top back contacts of relay 228, sleeve conductor 232 of the trunk, sleeve conductor 302 of the cord, normally made left outer contacts of key 305, which is now normal, lamp 303, resistance 338, to battery, lighting said lamp continuously as an indiction to the A operator that the calling subscriber has restored. This signal is not'repeated at this time to the B and C switchboards. When the called subscriber restores the usual sleeve supervisory circuit of the called subscribers line causes the lighting of lamp 539 in the well known manner. The supervisory relay 528 of the C switchboard completing cord releases thereby removing high resistance battery 529 from the ring conductor5l6. This has the effect of releasing relay 410 in the incoming trunk ITC. Battery through resistance 431 is therefore removed from the ring conductor 343 connecting the incoming trunk ITC with the outgoing trunk OTC. The removal of this battery from the ring conductor releases relay 321 which, in turn, releases relay 320. Since relay 329 isstill energized to ground from relay 323, battery thru the winding of relay 326 is likewise removed from the ring conductor 313 between the outgoing trunk OTC and the incoming trunk ITB. Due to the release of relay 320, battery through resistance 344 is connected through the bottom back contacts of relay 320, top front contacts of relay 329, repeating coil winding 332, conductor 342, to relay 407 energizing this relay and thus keeping relay 413 operated, which otherwise would have released by the release of relay 410. The release of relay 320 in the outgoing trunk OTC connects the grounded lower winding of relay 331 to lamp 307 of the connecting cord circuit, via top back contacts of relay v320, trunk sleeve conductor 311, cord sleeve'conductor 310, right outer normally made contacts of key 305, lamp 307, resistance 340 to battery. This will light lamp 307 steadily as an indication to the B operator that the called subscriber has restored.

The removal of battery from the ring conductor of the trunk OTC and ITC causes the release of relay 410 in the incoming trunk 1TB and the operations following the release of this relay in trunk OTB-1TB are identical with those described abovein connection with the trunk OTC-ITC so that lamp 307 at the A operators position islikewise made to light steadily. It will be noted, therefore, that while the release of the calling subscriber operates the calling subscribers supervisory lamp the Aboard, such signal is not repeated at the'intermediate and terminating boards, yet the release of the called subscriber, not only operates the called supervisory signal of the completing cord in the terminating office, but also causes the release signal to be repeated back to all the switchboards over the ring conductors of the connection train to light the called supervisory lamps of the respective cords at all intermediate switchboard positions as Well as at the originating position.

Both lamps 303 and 306 in the A operators cord circuit are noW lighted and the operator Will remove the cord. The removal of battery through the lamp 307 from sleeve conductor 311 causes relays 323, 329, 8.31 and 3:27 to release. Relays 407 and 41.3 in the incoming trunk release and in consequence relay l now operates over its grounded lower \vinding, back contacts of relay 413, sleeve conductor 421 of the trunk jack and sleeve conductor 502 of the cord, normally made left outer contacts of key 505, lamp 503, resistance 52 1 to battery.

from ground on the top front contacts of -relay e30 While relay 409 is held locked through its inner front contacts to ground on the bottom middle contacts of relay 430. Relay 330 now operates from battery through resistance 4:81 through the bottom back contacts of relay 429, top front contacts of relay e 05, Winding. 401 of the incoming trunk repeating coil, conductor .342, winding 832 of the outgoing trunk repeating coil, top back contacts of relay 329, Winding of relay 330 to ground. Relay 3.30 operates relay 322 over its-upper Winding. This operation serves to maintainan open circuit busy test on the outgoing end of the trunk until the B operator removes the cord. \Vhen the B operator removes her cord circuit relays 330, 322, 4330, 405 and i0?) release. Lamp 501 in the C operator's cord circuit will be lighted in the same manner causing her to release the connection in turn.

hat is claimed is:

1. In a telephone exchange system, a calling line, a charging device for said calling line, a called line, a local trunk, a pulse recordingeircuit in said local trunk, a plurality of interofice trunks, a pulsing circuit in each of said interotice trunks capable of generating a definite number of pulses, a link circuit,means for establishing a connection between said calling line and said called line over said local trunk, each of said interoliice trunks and said link circuit in the order named, means in said link circuit responsive to said called line, means in each of said intercttice trunks responsive to said latter means, means in said local trunk responsive said means in each of said interotfice trunks, means in one of said interoflice trunks connected to said local trunk responsive' to means in said local trunk for starting said pulsing circuit in said interoiiice trunk to generate its said definite number of pulses, means in each of said interoi'lice trunks responsive to the termination of operation of said pulsing circuit in said interoflice trunk connected to said local trunk to start said pulsing circuit in each of said interoi'lice trunks in succession to generate their respective number of pulses, means in each of said interoliice trunks responsive to pulses from tha; one of said interoilice trunks immediately succeeding in said connection, means in said local trunk responsive to pulses from said. interofiice trunk immediately connected therewith for recording all of said pulses in said pulse recording circuit, and ieans in said local trunk, under control of said pulse recording circuit, for operating said charging device a number of times in accordance with the number of all of said pulses recorded in said pulse recording circuit.

ng line, called line, a call charging device or saidcalling line, a local trunk, a pulse recording circuit in said local trunk, an interlice trunk, a pulsing circuit in said intere trunk capable of generating a definite number of pulses, means for extending said calling line to said called line over said local trunk and said interoi'lice trunk, means in said int-erotlicc trunk responsive to said called line, means in said local trunk responsive to said means in said interoliice trunk, means in said interoflice trunk responsive to said means in said local trunk for starting said impulse circuit to generate said definite group of pulses, means in said local trunk responsive to said pulses, means for recording said pulses in said pulse recording circuit, and means in said local trunk under control of said pulse recording circuit for operating said charin device a number of times in accordance with number of all of said pulses recorded in said pulse recording circuit.

3. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulsing circuit in said local trunk capable of generabing a definite number of pulses, a pulse recording circuit in said local trunk, means for extending said calling line to said called line over said local trunk, means in said local trunk responsive to .raid called line forstarting said pulsing circuit to generate said group of pulses, means in said local trunk responsive to said pulses for recording said pulses in said pulse recording circuit, and means in said local trunk responsive to said calling subscriber and under control of said pulse recording circuit for operating said chargingdevice a number oftimes in accord ance with number of all said pulses recorded in said impulse storing circuit. a

4. In a telephone exchange system, a callrality of interofiice trunks, a pulsing circuit '2. In a telephone exchange system, a callcircuit, means for establishing a connection between said calling line and said called line over said local trunk, each of said interolfice trunks and said link circuit in the order named, means in said link circuit responsive to said called line, means in each of said interofiice trunks responsive to said means in said link circuit means in said local trunk responsive to said means in each of said interofiice trunks, means in one of said intero'ifice trunks connected to said local trunk responsive to said means in said local trunk for starting said pulsing circuit in said interoifice trunk to generate its said definite number of pulses, meansin each of said interoifice trunks responsive to termination of operation of said pulsing circuit in said interofiice trunk connected to said local trunk to startsaid pulsing circuit in each of said interoifice trunks in succession to generate their respective said definite number of pulses, means in each of said interoflice trunks responsive to pulses from that one of said interoflice trunks immediately succeeding in said connection, means in said local trunk responsive to pulses from said interoflice trunk immediately connected therewith for recording all of said pulses in said pulse recording circuit, and means in said local trunk, responsive to restoration of said calling line and under control of said pulse recording circuit-for operating said charging device a number of times in accordance with number of all said pulses recorded in said pulse recording circuit.

5. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulse recording circuit in said local trunk, a plurality of interoffice trunks, a pulsing circuit in each of said interoflice trunks'capable of generating a definite number of pulses, a

link circuit, means for establishing a connection between said calling line and said called line over said local trunk, each of said interoflice trunks and said link circuit in the ordernamed, means in said link circuitresponsive to said called line, means in each of said interoffice trunks responsive successively to said means in said link circuit, means in said local trunk responsive to said means in eachof said interolfice trunks, means in one of said interoflice trunks connected to said local trunk responsive to said means in said local trunk for starting saidpulsing circuit in said interofiice trunk to generate its said definite number of pulses, means in each of said interoflice trunks responsive to the termination of operation of pulsing circuit in said interofiice trunk connected to said local trunk to start said pulsing circuit in each of said interoiiice trunks in succession to generate their respective number of pulses, means in each of said said interoffice trunk immediately succeeding in said connection, means in said local trunk responsive to pulses from said interofiice trunk immediately connected therewith for recording all of said pulses in said pulse recording circuit, and means in said local trunk responsive to restoration of said calling line and under control of said pulse recording circuit for operating said charging device a number of times in accordance with number of all said pulses recorded in said pulse recording circuit.

6. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulse recording circuit in said local trunk, an interoilice trunk, a pulsing circuit in said interoilice'trunk capable of generating a definite number of pulses, means for extending said calling line to said called line over said local trunk and said interofiice trunk, means in said interofiice trunk responsive to said called line, means in said local trunk responsive to said means in said interoifice trunk, means in said intcroflice trunk responsive to said means in said local trunk for starting said pulsing circuit to generate said definite number of pulses, means in said local trunk responsive to said pulses for recording said number of pulses in said recording circuit, and means in said local trunk responsive to restoration of said calling line and under control of said pulse recording circuit for operating said charging device a number of times in accordance with the number of all said pulses recorded in said local trunk.

7. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulse recording circuit in said local trunk, a plurality of two-way interoilice trunks, two pulsing circuits in each of said interofiice trunks each capable of generating a definite number of pulses, a link circuit, means for establishing a connection between said calling line and i said called line over-said local trunk, each of 'interofiice trunk depending on the direction ofsaid connection, to generate its definite number of pulses, means in each of said interoi'iice trunks responsive to termination of operation of said pulsing circuit in said interofiice trunk connected to saidlocal trunk to start said corresponding pulsing circuits in each of said interoflice trunks in succession to generate their respective said definite numberof pulses, means in each of said interoflicetrunks responsive'to pulses from that one ofsaid interofiice trunks immediately suc- CGGdlIlgJD said connection, means in said caltrunk responsive to pulses from said inrecording circuit for operating said charging device a number of times in accordance with the number ofall of said pulses recorded in saidpulse recording circuit.

8. In atelephone exchange system, a calling line, a called line, a call charging device 'forsaid calling line, a local trunk, a pulse recording circuit in said local trunk, a twoway interofiice trunk, two pulsing circuits in said interofiice trunk each capable of generating a. definite number of impulses, a link circuit, means for establishing a connection between "said calling line and said called line :over said local'trunk, said interolfice trunk -and said link circuit in the'order named,

-means in said interofiicetrunk, means in said i interofiice trunk responsive to said means in said local trunk for starting one of said pulsing circuits in said interofiice trunk depend ing upon the direction of said connection to generate its definite number of pulses, means in said local trunk responsive to said pulses for recording all of said pulses in said pulse recording circuit, and means in said local trunk responsive to restoration oi? said calling line and under control of said pulse recording circuit for operating said charging device a number of times in accordance with number of said pulses recorded insaid pulse recording circuit.

9. In a telephone exchange system a calling line,a called line, a call charging device 7 for said .callingline, a local trunk, a pulse recording circuit in said local trunk, a timing circuit in said local trunk, a plurality of interoflice trunks, a pulsing circuit in each of said interofiice trunks capable of generating definite number of pulses, a link circuit, means for establishing a connection between said calling line and said called line over said local trunk, each of said interofiice trunks and said link circuit in the order named, means in said link circuit responsive to said called line, means in each of said interoflice trunks responsive to said means in said link circuit, means in said local trunk responsive to said means in each of said interofiice trunks for operating said timing circuit, a prede- 'terinined time interval, means in said interfor starting said pulsing circuit to generate said definite group'of pulses, means in each of said interoflice trunks responsive to ter mination of operation of pulsing circuit in said interotiice trunk connected to said local trunk to start said pulsing circuit in each of said interoifice trunks in succession to generate their respective definite group of pulses, means in each of said interoifice trunks responsive to pulses from that one of said interofiice trunks immediately succeeding in said connection, means in said local trunk responsive to pulses from said interofiice trunk immediately connected therewith for recording all of said pulses in said pulse recording circuit, means responsive to said calling line after expiration of said predetermined time interval for generating another series of said definite number of pulses, and

for recording said other series of pulses in said pulse recording circuit, and means in said local trunk under control of said pulse recording circuit for operating said charging device a number of times in accordance with number of all of said pulses recorded in said pulse recording circuit.

10. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulse recording circuit in said local trunk, a timing circuit in said local trunk, an interoiiice trunk, a pulsing circuit in said interofiice trunk capable of generating a definite number of pulses, a link circuit, means for establishing a connection between said calling line and said called line over said local trunk, said interofiice trunk and said link circuit in the order named, means in said link circuit responsive to said called line, means in said interoffice trunk responsive to said means in said link circuit, means in said local. trunk responsive to said means in said interoifice trunk to start said timing circuit to measure a predetermined time interval, means in said interoifice trunk also responsive to said means in said local trunk for starting said pulsing circuit to generate said definite group of pulses, means in said local trunk responsive tosaid pulses for recording all of said pulses in said pulse recording circuit, means responsive to said calling line after expiration of said predetermined time interval for generating another series of said definite number of pulses, and for recording said other series of pulses in said pulse recording circuit, and means in said local trunk under control of said pulse recording circuitfor operating-said charging device a number of times in accord ance with a number of all of said pulses recorded in said pulse recording circuit.

11. In a telephone exchange system, a calling line, a called line, a call charging device for said calling line, a local trunk, a pulse recording circuit in said local trunk, a timing circuit in said local trunk, a plurality of twoway interoffice trunks, two pulsing circuits in .each of said interoliice trunks each capable-of generating a definite number of pulses, a link circuit,means for establishing a connection between said calling line and said called. line over said local trunk, each of said interoliice trunks and said link circuit in the order named, means in said link circuitresponsive to said called line, means in each of said interofiice trunks responsive to said means in. said link circuit, means in said local trunk respons1ve to said means in said interotfice trunks for starting said timing circuit to measure a predetermined time interval, means in said interofiice trunk connected to said local trunk also responsive to said means in said local trunk to start one of said two pulsing circuits in said interofiice trunk depending on the direction of said connection, to generate its definite number of pulses, means in each of said interofiicetrunks responsive to termination of operation of said pulsing circuit in said interoliice trunk connected to saidlocal trunk to start said corresponding pulsing circuit in each of said interoifice trunks in succession to generate their respective number of pulses, means in each ofsaid interofiice trunks responsive to pulses from,

that one of said interofiic'e trunks immediate- 1y succeeding in said connection, means in said local trunk responsive to pulses'from said interofiice trunk immediately connected therewith for recording all of said pulses in said pulse recording circuit, means respon sive to said calling line after the expiration of said'predetermined time interval for generatinganother series of said definite number 'of pulses, and for recording said other series of pulses in said pulse recording circuit, and means in sa d local trunl; under control of said pulses recording circuit for operating said charging device a number or" times in in said interofiice trunk responsive "to said cord circuit, an interofiice trunk, a pulsing circuit in said interoflicetrunk capable of generating a definite number of pulses, means for extending said calling line to saidcalled line over said first local cord circuit, saidinteroliice trunk and saidsecond local cord circuit, means in said second local cord circuit responsive to said called line, means in said interofiice trunk responsive to said means in said second local cord circuit, means in said first local cord circuit responsive to said means in said interoffice trunk for starting said timing circuit, to measure a predetermined time interval, means in said interofiice trunk alsoresponsive to said means in said first local cord circuit for starting said pulsing circuit to generate said definite number of pulses, means for operating said charging device a number of times in accordance with the number of all of said pulses, means in said timing circuit for operating said supervisory lamp after the expiration of saidpredetermined time interval, and means responsive to said calling line after the expiration of said predetermined time interval for generating another series of said definite number of pulses and operating said charging device a number of times in accordance with the number of pulses in said other series of pulses.

14. In atelephone exchange system, a calling line, a called line, a local trunk, a timing circuit in said local trunk,an interofiice trunk, a cord circuit having a supervisory lamp, means for extending said calling line to said called line over said local trunk, said cord circuit and said interoflice trunk, means in said interoflice trunk responsive to said called line, means in said local trunk responsive to said means in said interofiice trunk for starting said timing circuit, and means in said means'in saidlatter cord circuit for starting said pulsing circuit to generate said group of 'havinga supervisory lamp, a second local cord circuit, a'timing circuit in said first local 

